<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=\, initial-scale=1.0">
  <title>计数器</title>

</head>

<body>
  <div id="app">
    <h2>当前计数：{{counter}}</h2>
    <button v-on:click="counter ++">+</button>
    <button v-on:click="counter --">+</button>
  </div>

  <script src="./js/vue.js"></script>
  <script>
    const app = new Vue({
      el: "#app",
      data: {
        counter: 0
      }
    })
  </script>
</body>
</html>